MAGracing Forum

Hello Kim,
I assume that you are gluing 2mm cork onto MDF board so as to avoid breaking your router bits, when cutting the slot for the guide wire. Where I live there is a much less expensive way to build the track when both time and materials are considered.

Instead of gluing cork onto MDF, eliminate the cork and MDF and use GAF EnergyGuard Polyiso Insulation Board. This board is made of bilaminate facers (aluminum and kraft paper) bonded to a core of polyisocyanurate foam. The surface is smooth, tough, and wrinkle free. It’s also easy to cut a slot in it with a router.

The polyiso board is about as rigid/stiff as MDF but it is not as strong or resistant to compression. However, I would expect the rigid polyiso foam board to be more resistant to compression and abrasion than the cork you are using. The strength of the foam board should not be a problem with adequate support under the panels.

½ in thick MDF costs twice as much as ½ in GAF polyiso board and MDF weighs 8 times more. The GAF product is also available in 1 inch thick panels.

There are several manufacturers of polyiso board in the states. Perhaps there are a few in your part of the world. Note that not all polyisocyanurate foam insulation board has the same face skin. A smooth, wrinkle free, face skin is important for making a magracing track.
Ned

Would you have a picture of a trackpiece of this board.

Kim,

A couple of years ago I played around with the idea of producing and selling magracing track. I was thinking of making sections of track, perhaps as small as the plastic slot car track sold by Scalextric or Carrera, but probably larger. I decided that the best baseboard material available then was either ½” or 1” thick GAF EnergyGuard Polyiso Insulation Board. (GAF is a brand name.) This board is sold in sheets 4 ft wide and 8 ft long. It is easy to cut. One sheet ½’ thick costs about $13.00 and weighs only 4 lbs. It should be enough to make a circuit at least 32 ft long. That’s about $0.40 per linear foot for the base material. The cost of shipping should be relatively low since it is very light weight compared to MDF.

I abandoned the idea of making and selling ready to use track, because it was too difficult and time consuming to make a slot in the baseboard using a manually controlled router. A CNC router is the way to go but I was not willing to spend the time to learn how to use it, let alone the money to buy it. A CNC router is fast and accurate. It can turn out piece after piece, each identical to the others.

I also devised a method by which to connect the pieces together using cylinder magnets. But the method required the ability to precisely drill the holes for the magnets. I didn’t have the equipment to do that quickly either.

Below is a photo of a 1/2" thick piece of polyiso board with a piece of 0.032”(0.8mm) diameter wire embedded in it. I used a 0.035” (0.9mm) diameter fishtail router bit to make the slot about 0.035” deep. This is the only sample I made using polyiso board. I used a water-based latex white primer and sealer as the glue to hold the wire in the slot. I used a squeeze bottle to apply the paint in the slot. I used a wallpaper seam roller to press the wire into the slot and then wiped off the excess white paint with a 4” wide putty knife. (In retrospect, I think I should have made the width of the slot the same as the diameter of the wire.)
Click on the link below to see an image of a full 1 inch x 4ft x 8ft sheet.
https://docs.google.com/document/d/1qBm ... uUx-Q/edit

Here are a couple of closeups of the end incluidng the magnets, which hold tight to the heads of flat head screws in the bottom of the holes. The depth of the screws can be adjusted to precisely hold adjacent pieces of track together. Of course holes in ajoining pieces must lineup precisely. Of course the cars must be blocked from running over the magnets or they are likely to get stuck there.

Making by hand interchangeable pieces of track using my method is not possible. The precision needed to cut the pieces to size, to cut the slots, and drill the holes for the magnets is not possible by hand, such that the pieces are interchangeable. Cutting and gluing wire as well as painting the track surface is very easy. Perhaps there would be a market for track kits, which included the pre-cut polyiso board track pieces including the slots and holes, along with the needed wire, screws, and magnets to complete the track. Everything except for the paint which anyone can obtain locally.

A dumb question. You used the paper-side for track surface not the aluminum ?

Yes hand routing with the needed precision is hard. I had to do a small fix on my straights and stopped after doing one. The rest need to wait for the CNC. But at least I almost have a closed circle to test. Painting will probably do the trick of making it durable.

The face skin of the GAF polyiso board appears to be the same on both sides, except for the color. One side is very light grey with some red lettering and the other side is a slightly darker silver-grey. Apparently the aluminum and kraft paper are bonded together and then bonded to both sides of the core of polyisocyanurate foam.

Even after being wet and in the rain for 2 days, there is no delamination of the facer and foam core. See photos below of a ½” thick piece.
The magnets shown in the photos of my prior post are ¼” diameter x 1” cylinder magnets. I would expect them to be appropriate to hold together a magracing layout consisting of two or more full 4’ x 8’ sheets of 1” thick GAF polyiso board. I suspect that two 5mm x 5mm cylinder magnets at each end, would be adequate to hold together temporarily ½” thick pieces of track, which are less than 18” long.